Addressing Thin Film Thickness Metrology Challenges Of 14nm BEOL Layers

This paper describes a method to effectively monitor the film stack at different metal CMP process steps using a spectroscopic ellipsometer metrology tool. By proper modeling of the Cu dispersion and simulating the underlayer film information underneath the Cu pad, a single measurement recipe was developed which can be used to monitor each process step in the metal CMP process with stable and r... » read more